Apparatus for remotely controlling a materials handling vehicle

ABSTRACT

A finger-mounted remote control device capable of wirelessly transmitting a travel request signal to a materials handling vehicle. The finger-mounted remote control device includes a rigid mounting structure adapted to be mounted over at least one finger of an operator&#39;s hand; a mounting strap coupled to said rigid mounting structure for securing said rigid mounting structure to the at least one finger; a wireless transmitter/power pack unit coupled to said rigid mounting structure; and control structure coupled to said mounting structure and comprising a switch adapted to be actuated by an operator&#39;s thumb so as to cause said wireless transmitter/power pack unit to generate a travel request signal to the materials handling vehicle.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional PatentApplication Ser. No. 61/222,632, filed Jul. 2, 2009, entitled “APPARATUSFOR REMOTELY CONTROLLING A MATERIALS HANDLING VEHICLE;” U.S. ProvisionalPatent Application Ser. No. 61/234,866, filed Aug. 18, 2009, entitled“STEER CORRECTION FOR A REMOTELY OPERATED MATERIALS HANDLING VEHICLE;”and U.S. Provisional Patent Application Ser. No. 61/119,952, filed Dec.4, 2008, entitled “MULTIPLE ZONE SENSING FOR REMOTELY CONTROLLEDMATERIALS HANDLING VEHICLES” through International Patent ApplicationSerial No. PCT/US09/66789 and U.S. patent application Ser. No.12/631,007; the entire disclosures of each of which are herebyincorporated by reference herein. This application is a CIP ofInternational Patent Application Ser. No. PCT/US09/66789, filed Dec. 4,2009, entitled “MULTIPLE ZONE SENSING FOR MATERIALS HANDLING VEHICLES”and is a CIP of U.S. patent application Ser. No. 12/631,007, filed Dec.4, 2009, entitled “MULTIPLE ZONE SENSING FOR MATERIALS HANDLINGVEHICLES,” the entire disclosures of which are hereby incorporated byreference herein, and each of which claims the benefit of U.S.Provisional Patent Application Ser. No. 61/119,952, filed Dec. 4, 2008,entitled “MULTIPLE ZONE SENSING FOR REMOTELY CONTROLLED MATERIALSHANDLING VEHICLES”. This application is related to InternationalApplication No. ______, filed Dec. 30, 2009, entitled “APPARATUS FORREMOTELY CONTROLLING A MATERIALS HANDLING VEHICLE,” the entiredisclosure of which is hereby incorporated by reference herein.

BACKGROUND OF THE INVENTION

The present invention relates in general to materials handling vehicles,and more particularly, to apparatus for remotely controlling materialshandling vehicles.

Low level order picking trucks are commonly used for picking stock inwarehouses and distribution centers. Such order picking trucks typicallyinclude load carrying forks and a power unit having a platform uponwhich an operator may step and ride while controlling the truck. Thepower unit also has a steerable wheel and corresponding traction andsteering control mechanisms, e.g., a movable steering arm that iscoupled to the steerable wheel. A control handle attached to thesteering arm typically includes the operational controls necessary fordriving the truck and operating its load handling features.

In a typical stock picking operation, an operator fills orders fromavailable stock items that are located in storage areas provided along aplurality of aisles of a warehouse or distribution center. In thisregard, the operator drives a low level order picking truck to a firstlocation where item(s) are to be picked. In a pick process, the operatortypically steps off the truck, walks over to the appropriate locationand retrieves the ordered stock item(s) from their associated storagearea(s). The operator then places the picked stock on a pallet,collection cage or other support structure carried by the forks of theorder picking truck. Upon completing the pick process, the operatoradvances the order picking truck to the next location where item(s) areto be picked. The above process is repeated until all stock items on theorder have been picked.

It is not uncommon for an operator to repeat the pick process severalhundred times per order. Moreover, the operator may be required to picknumerous orders per shift. As such, the operator may be required tospend a considerable amount of time relocating and repositioning theorder picking truck, which reduces the time available for the operatorto spend picking stock.

BRIEF SUMMARY OF THE INVENTION

In accordance with a first aspect of the present invention, a materialshandling vehicle is provided comprising: a power unit; a load handlingassembly coupled to the power unit; at least one obstacle detectormounted to the power unit to detect an object located along a path oftravel of the power unit; a load sensor to generate a weight signalindicative of a weight of a load on the load handling assembly; and acontroller. The detector generates a distance signal upon detecting anobject corresponding to a distance between the detected object and thepower unit. The controller receives the distance signal and the weightsignal and generates a corresponding vehicle stop or maximum allowablespeed signal based on the distance and weight signals.

For a given first load weight, if a sensed object is located at adistance within a first detection zone, a stop signal may be generatedby the controller to effect stopping of the vehicle.

Wherein for the given first load weight, if a sensed object is locatedat a distance within a second detection zone spaced further away fromthe power unit than the first detection zone, then a first allowablemaximum vehicle speed is defined corresponding to the first load weightand an object being detecting in the second detection zone.

Wherein for the given first load weight, if a sensed object is locatedat a distance within a third detection zone spaced further away from thepower unit than the first and second detection zones, then a secondallowable maximum vehicle speed greater than the first maximum isdefined corresponding to the first load weight and an object beingdetected in the third detection zone.

In accordance with a second aspect of the present invention, a materialshandling vehicle is provided comprising: a power unit; a load handlingassembly coupled to the power unit; at least one first obstacle detectormounted at a first location on the power unit to detect an objectlocated along a path of travel of the power unit beyond or outside adead zone of the first detector; and at least one second obstacledetector mounted at a second location on the power unit, spaced from thepower unit first location, and capable of detecting an object in thedead zone of the first obstacle detector.

The first obstacle detector may be located at a front portion of thepower unit. The second obstacle detector may be spaced away from thefirst obstacle detector in a direction towards the load handlingassembly.

In accordance with a third aspect of the present invention, afinger-mounted remote control device is provided capable of wirelesslytransmitting a travel request signal to a materials handling vehiclecomprising: a rigid mounting structure adapted to be mounted over atleast one finger of an operator's hand; a mounting strap coupled to therigid mounting structure for securing the rigid mounting structure tothe at least one finger; a wireless transmitter/power pack unit coupledto the rigid mounting structure; and control structure coupled to themounting structure and comprising a switch adapted to be actuated by anoperator's thumb so as to cause the wireless transmitter/power pack unitto generate a travel request signal to the materials handling vehicle.

Preferably, the mounting strap contacts at least one finger of theoperator's hand.

The rigid mounting structure may be formed from a rigid polymericmaterial.

Preferably, substantially the entirety of the remote control device ismounted and positioned directly over the at least one finger of theoperator's hand. For example, approximately 60% or more of the wirelesstransmitter/power pack unit is positioned directly over the at least onefinger of the operator's hand.

In accordance with a fourth aspect of the present invention, afinger-mounted remote control device capable of wirelessly transmittinga travel request signal to a materials handling vehicle is providedcomprising: a mounting structure adapted to be mounted over at least onefinger of an operator's hand; a mounting strap coupled to the mountingstructure for securing the mounting structure to the at least onefinger; a wireless transmitter/power pack unit coupled to the mountingstructure; and control structure coupled to the mounting structure andcomprising a switch adapted to be actuated by an operator's thumb so asto cause the wireless transmitter/power pack unit to generate a travelrequest signal to the materials handling vehicle. Substantially theentirety of the control device is mounted and positioned directly overthe at least one finger of the operator's hand.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is an illustration of a materials handling vehicle capable ofremote control according to various aspects of the present invention;

FIG. 2 is a schematic diagram of several components of a materialshandling vehicle capable of remote control according to various aspectsof the present invention;

FIG. 3 is a schematic diagram illustrating detection zones of amaterials handling vehicle according to various aspects of the presentinvention;

FIG. 4 is a schematic diagram illustrating an exemplary approach fordetecting an object according to various aspects of the presentinvention;

FIG. 5 is a schematic diagram illustrating a plurality of detectionzones of a materials handling vehicle according to further aspects ofthe present invention;

FIGS. 6 and 8 illustrate a materials handling vehicle having first andsecond spaced-apart obstacle detectors;

FIG. 7 is a schematic view illustrating a materials handling vehiclehaving obstacle detectors located only at a front of the vehicle;

FIGS. 9A and 9B are views illustrating a finger-mounted remote controldevice mounted to fingers of an operator;

FIGS. 10A, 10C, 10D, and 10E illustrate various views of thefinger-mounted remote control device of FIGS. 9A and 9B;

FIG. 10B is an exploded view of the finger-mounted remote control deviceof FIGS. 9A and 9B;

FIG. 10F is a cross sectional view of the finger-mounted remote controldevice of FIGS. 9A and 9B;

FIG. 11 illustrates example lookup table data;

FIG. 12 is a flow chart of a method of implementing steer correctionaccording to various aspects of the present invention; and

FIG. 13 is a schematic illustration of a materials handling vehicletraveling down a narrow warehouse aisle under remote wireless operation,which is automatically implementing a steer correction maneuveraccording to various aspects of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

In the following detailed description of the illustrated embodiments,reference is made to the accompanying drawings that form a part hereof,and in which is shown by way of illustration, and not by way oflimitation, specific embodiments in which the invention may bepracticed. It is to be understood that other embodiments may be utilizedand that changes may be made without departing from the spirit and scopeof various embodiments of the present invention.

Low Level Order Picking Truck:

Referring now to the drawings, and particularly to FIG. 1, a materialshandling vehicle, which is illustrated as a low level order pickingtruck 10, includes in general a load handling assembly 12 that extendsfrom a power unit 14. The load handling assembly 12 includes a pair offorks 16, each fork 16 having a load supporting wheel assembly 18. Theload handling assembly 12 may include other load handling features inaddition to, or in lieu of the illustrated arrangement of the forks 16,such as a load backrest, scissors-type elevating forks, outriggers orseparate height adjustable forks. Still further, the load handlingassembly 12 may include load handling features such as a mast, a loadplatform, collection cage or other support structure carried by theforks 16 or otherwise provided for handling a load supported and carriedby the truck 10.

The illustrated power unit 14 comprises a step-through operator'sstation dividing a first end section of the power unit 14 (opposite theforks 16) from a second end section (proximate the forks 16). Thestep-through operator's station provides a platform upon which anoperator may stand to drive the truck 10. The platform also provides aposition from which the operator may operate the load handling featuresof the truck 10. Presence sensors 58 may be provided, e.g., on, above,or under the platform floor of the operator's station. Still further,presence sensors 58 may be otherwise provided about the operator'sstation to detect the presence of an operator on the truck 10. In theexemplary truck of FIG. 1, the presence sensors 58 are shown in dashedlines indicating that they are positioned under the platform floor.Under this arrangement, the presence sensors 58 may comprise loadsensors, switches, etc. As an alternative, the presence sensors 58 maybe implemented above the platform 56, such as by using ultrasonic,capacitive or other suitable sensing technology.

An antenna 66 extends vertically from the power unit 14 and is providedfor receiving control signals from a corresponding remote control device70. The remote control device 70 may comprise a transmitter that is wornor otherwise maintained by the operator. As an example, the remotecontrol device 70 may be manually operable by an operator, e.g., bypressing a button or other control, to cause the device 70 to wirelesslytransmit at least a first type signal designating a travel request tothe vehicle, thus requesting the vehicle to travel by a predeterminedamount. The remote control device 70 may comprise a glove-like structure70, see FIG. 1, such as disclosed in U.S. Provisional Patent ApplicationSer. No. 60/825,688, filed Sep. 14, 2006 entitled “SYSTEMS AND METHODSOF REMOTELY CONTROLLING A MATERIALS HANDLING VEHICLE,” U.S. patentapplication Ser. No. 11/855,310, entitled “SYSTEMS AND METHODS OFREMOTELY CONTROLLING A MATERIALS HANDLING VEHICLE,” U.S. patentapplication Ser. No. 11/855,324, entitled “SYSTEMS AND METHODS OFREMOTELY CONTROLLING A MATERIALS HANDLING VEHICLE,” the disclosures ofeach of which are incorporated by reference herein.

The remote control device may alternatively comprise a finger-mountedremote control device 170, as illustrated in FIGS. 9A, 9B and 10A-10F.The finger-mounted remote control device 170 comprises, in theillustrated embodiment, a polymeric rigid base 172, a polymeric rigidupper housing 174 and a pivotable latch 173 coupled to the base 172 viaa generally straight spring rod 273 so as to be spring biased to ahome/locking position, as shown in FIG. 10F. The latch 173 can be movedgenerally linearly/laterally against the bias of the spring bar 273 in adirection, designated by arrow A in FIG. 10F, to a release position. Thebase and upper housing 172 and 174 are coupled together via screws 273Aand define a docking area 175 for removably receiving a wirelesstransmitter/power pack unit 176. The base and upper housing 172 and 174may alternatively be coupled together via an adhesive or an ultrasonicwelding operation. The wireless transmitter/power pack unit 176 maycomprise the components found in the communications device set out inU.S. patent application Ser. No. 11/855,324, entitled “SYSTEMS ANDMETHODS OF REMOTELY CONTROLLING A MATERIALS HANDLING VEHICLE,” thedisclosure of which is incorporated by reference herein. In theillustrated embodiment, a transmitter antenna is also housed in thewireless transmitter/power pack unit 176.

The wireless transmitter/power pack unit 176 is releasably held withinthe docking area 175 via the latch 173, see FIG. 10F. A contact plate178 is mounted to the base 172 via screws or pins molded into the base172 and swaged over the plate (not shown) and includes one or morecontacts (not shown) on an upper surface 178A of the contact plate 178for engaging corresponding contacts on the wireless transmitter/powerpack unit 176. The wireless transmitter/power pack unit 176 can beremoved from the docking area 175 for recharging a power pack or batterycontained therein. It is also contemplated that the wirelesstransmitter/power pack unit 176 may be non-removable, i.e., integralwith or sealed within the base 172 and upper housing 174. In this latterembodiment, the wireless transmitter/power pack unit 176 includes areceptacle (not shown) for receiving an AC adapter for charging thepower or battery pack.

The rigid base 172 is provided with a first slot 172A for receiving aholding strap 190, which will be discussed below, see FIGS. 10D and 10E.The rigid base 172 also has a finger-engaging extension 172B extendingdownward from a lower surface 172C of the base 172 so as to define aportion of a first finger receiving area 200 and a second fingerreceiving area 202, see FIG. 10F.

The finger-mounted remote control device 170 further comprises controlstructure 180. The control structure 180 comprises a backing plate 182having a recess 282A and a two-state switch 183 received in the recess282A. Conductors or wires (not shown) extend from the switch 183 to alower surface 178B of the contact plate 178 such that signals generatedby the switch 183 when activated, as will be discussed below, aredelivered via the conductors to the contact plate 178 and from thecontact plate 178 to the transmitter/power pack unit 176. The backingplate 182 further comprises four bores 182A and a curved lower surface182C, which defines a portion of the first finger receiving area 200,see FIGS. 10B, 10E and 10F.

The control structure 180 further comprises a button and support plateassembly 184. The support plate assembly 184 may be formed from a rigidpolymeric material and comprises four bores 184A that align with thefour bores 182A in the backing plate 182. A “Go” button 184B, defined bya flexible polymeric member, is integral with or coupled to asurrounding portion of the support plate 184. The button 184B covers theswitch 183. A lower portion 185 of the support plate assembly 184 isprovided with a second slot 185A for receiving the holding strap 190. Acurved lower surface 185B of the support plate lower portion 185 definesa portion of the first finger receiving area 200, see FIGS. 10E and 10F.An outer cover plate 186 having an opening 186A is fitted over thebutton and support plate assembly 184. Four screws 186B extend throughthe bores 182A in the backing plate 182 and the bores 184A in thesupport plate 184 and are received in threaded openings (not shown) inthe outer cover plate 186. The cover plate 186 further comprises firstand second laterally extending ears 286 provided with bores 286A throughwhich two of the bolts 273A, noted above, pass. Hence, the bolts 273couple the control structure 180 to the base and upper housing 172 and174.

As illustrated in FIGS. 9A and 9B, the remote control device 170 isadapted to be fitted over index and middle fingers F₁ and F_(M) of anoperator, wherein the index finger is received in the first fingerreceiving area 200 and the middle finger is received in the secondfinger receiving area 202. Both right and left hand versions of thecontrol device 170 may be created.

The finger-mounted remote control device 170 is compact. As is apparentfrom FIGS. 9A and 9B, substantially the entirety of the remote controldevice 170 is mounted and positioned directly over the index and middlefingers F₁ and F_(M) of an operator. Hence, approximately 60% or more ofthe wireless transmitter/power pack unit 176 is positioned directly overthe operator's fingers F while a small remaining portion extends overthe hand portion HP extending away from the base F_(B) of the fingers F,see FIG. 9.

The control device 170 is releasably held on the operator's index andmiddle fingers via the holding strap 190. A first end 190A of theholding strap 190 is threaded through the first slot 172A in the rigidbase 172 and the second slot 185A in the lower portion 185 of thesupport plate 184. A second end 190B of the strap 190 is enlarged so asnot to pass through the first slot 172A, see FIG. 10E. A first portion190C of the strap 190, extending generally from the strap second end190B to the second slot 185A, extends across the operator's index andmiddle fingers, see FIG. 9. A second portion 190D of the strap 190,extending generally from the second slot 185A to the strap first end190A, is folded back onto the strap first portion 190C and releasablyattached to the strap first portion 190C such as by hook and loopfasteners, i.e., Velcro (trademark) or like fastening structure. It isnoted that other types of mounting straps 190 may be used, such as, forexample expandable/flexible straps, rigid or flexible rings, etc.

It is contemplated that the finger-mounted remote control device 170 maybe worn by an operator over a glove. In the illustrated embodiment, thefinger-mounted remote control device 170 is durable and long lastingsince the rigid base 172, the upper housing 174 and the outer coverplate 186 are preferably formed from a durable and rigid polymericmaterial, such as acrylonitrile butadiene styrene (ABS), polycarbonateor nylon. The rigid base 172, the upper housing 174 and the outer coverplate 186 define a durable, generally non-flexible and rigid mountingstructure 270.

An operator can easily manually actuate the go button 184B via histhumb, thereby actuating the switch 183, to cause the wirelesstransmitter/power pack unit 176 to wirelessly transmit at least a firsttype signal designating a travel request or command to the vehicle. Itis contemplated that the travel request may result in the vehicle 10traveling by a predetermined distance or for a predetermined amount oftime. It is also contemplated that a brief actuation of the go button184B may result in the vehicle 10 traveling for a predetermined distanceor for a predetermined amount of time, while a prolonged actuation ofthe go button 184B may result in continuous movement of the vehicle 10until the go button 184B is released.

It is noted that the finger-mounted remote control device 170 describedherein is an exemplary configuration and may be structurally modifiedwithout departing from the spirit and scope of the invention. Forexample, one or more components of the finger-mounted remote controldevice 170 may be combined in an integral component, or components maybe substituted for alternate components that effect a similar/identicalpurpose. As a few examples, the support plate assembly 184 and the outercover plate 186 may be combined into an integral piece, which integralpiece may be coupled to the backing plate 182 by structure other thanscrews 186B.

The truck 10 also comprises one or more obstacle sensors 76, which areprovided about the vehicle, e.g., towards the first end section of thepower unit 14 and/or to the sides of the power unit 14. The obstaclesensors 76 include at least one contactless obstacle sensor on thevehicle, and are operable to define at least one detection zone, eachdetection zone defining an area at least partially in front of a forwardtraveling direction of the vehicle when the vehicle is traveling underremote control in response to a travel request as will be described ingreater detail herein. The obstacle sensors 76 may comprise any suitableproximity detection technology, such as an ultrasonic sensors, opticalrecognition devices, infrared sensors, laser sensors, etc., which arecapable of detecting the presence of objects/obstacles within thepredefined detection zones of the power unit 14.

In practice, the truck 10 may be implemented in other formats, stylesand features, such as an end control pallet truck that includes asteering tiller arm that is coupled to a tiller handle for steering thetruck. In this regard, the truck 10 may have similar or alternativecontrol arrangements to that shown in FIG. 1. Still further, the truck10, remote control system and/or components thereof, may comprise anyadditional and/or alternative features, such as set out in U.S.Provisional Patent Application Ser. No. 60/825,688, filed Sep. 14, 2006entitled “SYSTEMS AND METHODS OF REMOTELY CONTROLLING A MATERIALSHANDLING VEHICLE;” U.S. patent application Ser. No. 11/855,310, filedSep. 14, 2007 entitled “SYSTEMS AND METHODS OF REMOTELY CONTROLLING AMATERIALS HANDLING VEHICLE;” U.S. patent application Ser. No.11/855,324, filed Sep. 14, 2007 entitled “SYSTEMS AND METHODS OFREMOTELY CONTROLLING A MATERIALS HANDLING VEHICLE;” U.S. ProvisionalPatent Application Ser. No. 61/119,952, filed Dec. 4, 2008 entitled“MULTIPLE ZONE SENSING FOR REMOTELY CONTROLLED MATERIALS HANDLINGVEHICLES;” U.S. Provisional Patent Application Ser. No. 61/234,866,filed Aug. 18, 2009, entitled “STEER CORRECTION FOR A REMOTELY OPERATEDMATERIALS HANDLING VEHICLE;” and/or U.S. Pat. No. 7,017,689, issued Mar.28, 2006, entitled “ELECTRICAL STEERING ASSIST FOR MATERIAL HANDLINGVEHICLE,” the entire disclosures of which are each hereby incorporatedby reference herein.

Control System for Remote Control of a Low Level Order Picking Truck:

Referring to FIG. 2, a block diagram 100 illustrates a controlarrangement for integrating remote control commands with the truck 10.The antenna 66 is coupled to a receiver 102 for receiving commandsissued by the remote control device 70, 170. The receiver 102 passes thereceived control signals to a controller 103, which implements theappropriate response to the received commands. The response may compriseone or more actions, or inaction, depending upon the logic that is beingimplemented. Positive actions may comprise controlling, adjusting orotherwise affecting one or more components of the truck 10. Thecontroller 103 may also receive information from other inputs 104, e.g.,from sources such as the presence sensors 58, the obstacle sensors 76,switches, load sensors, encoders and other devices/features available tothe truck 10 to determine appropriate action in response to the receivedcommands from the remote control device 70, 170. The sensors 58, 76,etc. may be coupled to the controller 103 via the inputs 104 or via asuitable truck network, such as a control area network (CAN) bus 110.

In an exemplary arrangement, the remote control device 70, 170 isoperative to wirelessly transmit a control signal that represents afirst type signal such as a travel command to the receiver 102 on thetruck 10. The travel command is also referred to herein as a “travelsignal”, “travel request” or “go signal”. The travel request is used toinitiate a request to the truck 10 to travel by a predetermined amount,e.g., to cause the truck 10 to advance or jog in a first direction by alimited travel distance. The first direction may be defined, forexample, by movement of the truck 10 in a power unit 14 first, i.e.,forks 16 to the back, direction. However, other directions of travel mayalternatively be defined. Moreover, the truck 10 may be controlled totravel in a generally straight direction or along a previouslydetermined heading. Correspondingly, the limited travel distance may bespecified by an approximate travel distance, travel time or othermeasure.

Thus, a first type signal received by the receiver 102 is communicatedto the controller 103. If the controller 103 determines that the travelsignal is a valid travel signal and that the current vehicle conditionsare appropriate (explained in greater detail below), the controller 103sends a signal to the appropriate control configuration of theparticular truck 10 to advance and then stop the truck 10. As will bedescribed in greater detail herein, stopping the truck 10 may beimplemented, for example, by either allowing the truck 10 to coast to astop or by applying a brake to stop the truck.

As an example, the controller 103 may be communicably coupled to atraction control system, illustrated as a traction motor controller 106of the truck 10. The traction motor controller 106 is coupled to afraction motor 107 that drives at least one steered wheel 108 of thetruck 10. The controller 103 may communicate with the traction motorcontroller 106 so as to accelerate, decelerate, adjust and/or otherwiselimit the speed of the truck 10 in response to receiving a travelrequest from the remote control device 70, 170. The controller 103 mayalso be communicably coupled to a steer controller 112, which is coupledto a steer motor 114 that steers at least one steered wheel 108 of thetruck 10. In this regard, the truck may be controlled by the controller103 to travel an intended path or maintain an intended heading inresponse to receiving a travel request from the remote control device70, 170.

As yet another illustrative example, the controller 103 may becommunicably coupled to a brake controller 116 that controls truckbrakes 117 to decelerate, stop or otherwise control the speed of thetruck in response to receiving a travel request from the remote controldevice 70, 170. Still further, the controller 103 may be communicablycoupled to other vehicle features, such as main contactors 118, and/orother outputs 119 associated with the truck 10, where applicable, toimplement desired actions in response to implementing remote travelfunctionality.

According to various aspects of the present invention, the controller103 may communicate with the receiver 102 and with the tractioncontroller 106 to operate the vehicle under remote control in responseto receiving travel commands from the associated remote control device70, 170. Moreover, the controller 103 may be configured to perform afirst action if the vehicle is traveling under remote control inresponse to a travel request and an obstacle is detected in a first oneof the detection zones. The controller 103 may be further configured toperform a second action different from the first action if the vehicleis traveling under remote control in response to a travel request and anobstacle is detected in a second one of the detection zones. In thisregard, when a travel signal is received by the controller 103 from theremote control device 70, 170, any number of factors may be consideredby the controller 103 to determine whether the travel signal should beacted upon and what action(s) should be taken, if any. The particularvehicle features, the state/condition of one or more vehicle features,vehicle environment, etc., may influence the manner in which controller103 responds to travel requests from the remote control device 70, 170.

The controller 103 may also refuse to acknowledge the travel signaldepending upon vehicle condition(s), e.g., that relate to environmentalor/ operational factor(s). For example, the controller 103 may disregardan otherwise valid travel request based upon information obtained fromone or more of the sensors 58, 76. For example, according to variousaspects of the present invention, the controller 103 may optionallyconsider factors such as whether an operator is on the truck 10 whendetermining whether to respond to a travel command from the remotecontrol device 70, 170. For example, as noted above, the truck 10 maycomprise at least one presence sensor 58 for detecting whether anoperator is positioned on the vehicle. In this regard, the controller103 may be further configured to respond to a travel request to operatethe vehicle under remote control when the presence sensor(s) 58designate that no operator is on the vehicle.

Any other number of reasonable conditions may also/alternatively beimplemented by the controller 103 to interpret and take action inresponse to received signals. Other exemplary factors are set out ingreater detail in U.S. Provisional Patent Application Ser. No.60/825,688, filed Sep. 14, 2006 entitled “SYSTEMS AND METHODS OFREMOTELY CONTROLLING A MATERIALS HANDLING VEHICLE,” U.S. patentapplication Ser. No. 11/855,310, filed Sep. 14, 2007 entitled “SYSTEMSAND METHODS OF REMOTELY CONTROLLING A MATERIALS HANDLING VEHICLE,” U.S.patent application Ser. No. 11/855,324, filed Sep. 14, 2007 entitled“SYSTEMS AND METHODS OF REMOTELY CONTROLLING A MATERIALS HANDLINGVEHICLE,” U.S. Provisional Patent Application Ser. No. 61/119,952, filedDec. 4, 2008 entitled “MULTIPLE ZONE SENSING FOR REMOTELY CONTROLLEDMATERIALS HANDLING VEHICLES,” and U.S. Provisional Patent ApplicationSer. No. 61/234,866, filed Aug. 18, 2009, entitled “STEER CORRECTION FORA REMOTELY OPERATED MATERIALS HANDLING VEHICLE,” the disclosures ofwhich are each already incorporated by reference herein.

Upon acknowledgement of a travel request, the controller 103 interactswith the traction motor controller 106, e.g., directly, indirectly, viathe CAN bus 110, etc., to advance the truck 10. Depending upon theparticular implementation, the controller 103 may interact with thefraction motor controller 106 to advance the truck 10 by a predetermineddistance. Alternatively, the controller 103 may interact with thetraction motor controller 106 to advance the truck 10 for a period oftime in response to the detection and maintained actuation of a travelcontrol on the remote 70. Further alternatively, the truck 10 may beconfigured to jog for as long as a travel control signal is received.Still further alternatively, the controller 103 may be configured to“time out” and stop the travel of the truck 10 based upon apredetermined event, such as exceeding a predetermined time period ortravel distance regardless of the detection of maintained actuation of acorresponding control on the remote control device 70, 170.

The remote control device 70, 170 may also be operative to transmit asecond type signal, such as a “stop signal”, designating that the truck10 should brake and/or otherwise come to rest. The second type signalmay also be implied, e.g., after implementing a “travel” command, e.g.,after the truck 10 has traveled a predetermined distance, traveled for apredetermined time, etc., under remote control in response to the travelcommand. If the controller 103 determines that the signal is a stopsignal, the controller 103 sends a signal to the traction controller106, the brake controller 116 and/or other truck component to bring thetruck 10 to a rest. As an alternative to a stop signal, the second typesignal may comprise a “coast signal”, designating that the truck 10should coast, eventually slowing to rest or a “controlled decelerationsignal.”

The time that it takes to bring the truck 10 to a complete rest mayvary, depending for example, upon the intended application, theenvironmental conditions, the capabilities of the particular truck 10,the load on the truck 10 and other similar factors. For example, aftercompleting an appropriate jog movement, it may be desirable to allow thetruck 10 to “coast” some distance before coming to rest so that thetruck 10 stops slowly. This may be achieved by utilizing regenerativebraking to slow the truck 10 to a stop. Alternatively, a brakingoperation may be applied after a predetermined delay time to allow apredetermined range of additional travel to the truck 10 after theinitiation of the stop operation. It may also be desirable to bring thetruck 10 to a relatively quicker stop, e.g., if an object is detected inthe travel path of the truck 10 or if an immediate stop is desired aftera successful jog operation. For example, the controller may applypredetermined torque to the braking operation. Under such conditions,the controller 103 may instruct the brake controller 116 to apply thebrakes 117 to stop the truck 10.

Detection Zones of a Materials Handling Vehicle:

Referring to FIG. 3, according to various aspects of the presentinvention, one or more obstacle sensors 76 are configured so as tocollectively enable detection of objects/obstacles within multiple“detection zones”. In this regard, the controller 103 may be configuredto alter one or more operational parameters of the truck 10 in responseto detection of an obstacle in one or more of the detection zones as setout in greater detail herein. The control of the vehicle utilizingdetection zones may be implemented when an operator is riding/drivingthe vehicle. The control of the vehicle utilizing detection zones mayalso be integrated with supplemental remote control as set out anddescribed more fully herein. When an operator is riding the vehicle theoperator may have the option of disabling one or more of the detectionzones and/or one or more of the responses of the controller when thedetectors detect an object, as described below.

Although six obstacle sensors 76 are shown for purposes of clarity ofdiscussion herein, any number of obstacle sensors 76 may be utilized.The number of obstacle sensors 76 will likely vary, depending upon thetechnology utilized to implement the sensor, the size and/or range ofthe detection zones, the number of detection zones, and/or otherfactors.

In the illustrative example, a first detection zone 78A is locatedproximate to the power unit 14 of the truck 10. A second detection zone78B is defined adjacent to the first detection zone 78A and appears togenerally circumscribe the first detection zone 78A. A third area isalso conceptually defined as all area outside the first and seconddetection zones 78A, 78B. Although the second detection zone 78B isillustrated as substantially circumscribing the first detection zone78A, any other practical arrangement that defines the first and seconddetection zones 78A, 78B may be realized. For example, all or certainportions of the detection zones 78A, 78B may intersect, overlap or bemutually exclusive. Moreover, the particular shape of the detectionzones 78A, 78B can vary. Still further, any number of detection zonesmay be defined, further examples of which are described in greaterdetail herein.

Still further, the detection zones need not surround the entire truck10. Rather, the shape of the detection zones may be dependent upon theparticular implementation as set out in greater detail herein. Forexample, if the detection zones 78A, 78B are to be used for speedcontrol while the truck 10 is moving without an operator riding thereon,under remote travel control in a power unit first (forks to the rear)orientation, then the detection zones 78A, 78B may be oriented forwardof the direction of travel of the truck 10. However, the detection zonescan also cover other areas, e.g., adjacent to the sides of the truck 10.

According to various aspects of the present invention, the firstdetection zone 78A may further designate a “stop zone”. Correspondingly,the second detection zone 78B may further designate a “first speedzone”. Under this arrangement, if an object, e.g., some form of obstacleis detected within the first detection zone 78A, and the materialshandling vehicle 10 is traveling under remote control in response to atravel request, then the controller 103 may be configured to implementan action such as a “stop action” to bring the truck 10 to a stop. Inthis regard, travel of the truck 10 may continue once the obstacle isclear, or a second, subsequent travel request from the remote controldevice 70, 170 may be required to restart travel of the truck 10.

If a travel request is received from the remote control device 70, 170while the truck is at rest and an object is detected within the firstdetection zone 78A, then the controller 103 may refuse the travelrequest and keep the truck at rest until the obstacle is cleared out ofthe stop zone.

If an object/obstacle is detected within the second detection zone 78B,and the materials handling vehicle 10 is traveling under remote controlin response to a travel request, then the controller 103 may beconfigured to implement a different action. For example, the controller103 may implement a first speed reduction action to reduce the speed ofthe vehicle to a first predetermined speed, such as where the vehicle istraveling at a speed greater than the first predetermined speed.

Thus, assume the truck 10 is traveling in response to implementing atravel request from the remote control device at a speed V2 asestablished by a set of operating conditions where the obstacle sensors76 do not detect an obstacle in any detection zone. If the truck isinitially at rest, the truck may be accelerated up to speed V2. Thedetection of an obstacle within the second detection zone 78B (but notthe first detection zone 78A) may cause the truck 10, e.g., via thecontroller 103 to alter at least one operational parameter, e.g., toslow down the truck 10 to a first predetermined speed V1, which isslower than the speed V2. That is, V1<V2. Once the obstacle is clearedfrom the second detection zone 78B, the truck 10 may resume its speedV2, or the truck 10 may maintain its speed V1 until the truck stops andthe remote control device 70, 170 initiates another travel request.Still further, if the detected object is subsequently detected withinthe first detection zone 78A, the truck 10 will be stopped as describedmore fully herein.

Assume as an illustrative example, that the truck 10 is configured totravel at a speed of approximately 2.5 miles per hour (mph) (4Kilometers per hour (Km/h)) if the truck 10 is traveling without anoperator onboard and is under remote control in response to a travelrequest from a corresponding remote control 70, so long as no object isdetected in a defined detection zone. If an obstacle is detected in thesecond detection zone 78B, then the controller 103 may adjust the speedof the truck 10 to a speed of approximately 1.5 mph (2.4 Km/h) or someother speed less than 2.5 miles per hour (mph) (4 Kilometers per hour(Km/h)). If an obstacle is detected in the first detection zone 78A,then the controller 103 stops the truck 10.

The above example assumes that the truck 10 is traveling under remotecontrol. In this regard, the obstacle sensors 76 can be used to adjustthe operating conditions of the unoccupied truck 10. However, theobstacle sensors 76 and corresponding controller logic may also beoperative when the truck 10 is being driven by an operator, e.g., ridingon the platform or other suitable location of the truck 10. Thus,according to various aspects of the present invention, the controller103 may stop the vehicle or refuse to allow the vehicle to move if anobject is detected within the stop zone 78A regardless of whether thetruck is being driven by an operator or operating under remote control.Correspondingly, depending upon the specific implementation, its speedcontrol capability of the second detection zone 78B may be implementedregardless of whether the vehicle is operating under remote control, orwhether an operator is riding on the vehicle while driving it.

However, according to various aspects of the present invention, theremay be situations where it is desirable to disable one or more of thedetection zones when the truck 10 is being driven by an operator. Forexample, it may be desirable to override/disable the obstacle sensors76/controller logic while the operator is driving the truck 10regardless of external conditions. As a further example, it may bedesirable to override/disable the obstacle sensors 76/controller logicwhile the operator is driving the truck 10 to allow the operator tonavigate the truck 10 in tight quarters, e.g., to navigate tight spaces,travel around corners, etc., that might otherwise activate one or moreof the detection zones. As such, the activation of the controller logicto utilize the detection of objects in the detection zones to helpcontrol the vehicle while the vehicle is occupied by an operator,according to various aspects of the present invention, may be manuallycontrolled, programably controlled or otherwise selectively controlled.

According to other aspects of the present invention, it may be desirableto disable one or more of the detection zones when an operator iswalking alongside the truck 10 and controlling operation of the truck 10with a supplemental control, such as a jog switch/button, e.g., locatedon a side portion of the truck 10. Such a jog switch may be used to moveor jog the truck 10 in a forward direction at a predetermined andpreferably low speed, as will be apparent to those skilled in the art.For example, it may be desirable to override/disable the obstaclesensors 76/controller logic while the operator is actuating the jogswitch regardless of external conditions. As a further example, it maybe desirable to override/disable the obstacle sensors 76/controllerlogic while the operator is actuating the jog switch to allow theoperator to navigate the truck 10 in tight quarters, e.g., to navigatetight spaces, travel around corners, etc., that might otherwise activateone or more of the detection zones. As yet a further example, upon theoperator releasing the jog switch, the truck 10 may coast to a stop.Upon the releasing of the jog switch and the truck 10 coasting, one ormore of the disabled detection zones may be enabled, i.e., by enablingone or more of the obstacle sensors 76/controller logic.

Referring to FIG. 4, according to further aspects of the presentinvention, one or more of the obstacle sensors 76 may be implemented byultrasonic technology, laser technology, or other suitable contactlesstechnology capable of a distance measurement and/or positiondetermination. Thus, the distance to an object can be measured, and/or adetermination may be made so as to ascertain whether the detected objectis within a detection zone 78A, 78B, e.g., by virtue of the distance ofthe object from the truck 10. As an example, an obstacle sensor 76 maybe implemented by an ultrasonic sensor or transducer that provides a“ping” signal, such as a high frequency signal generated by a piezoelement. The ultrasonic sensor 76 then rests and listens for a response.In this regard, time of flight information may be determined andutilized to define each zone. Thus, a controller, e.g., the controller103 or a controller specifically associated with the obstacle sensors 76may utilize software that looks at time of flight information todetermine whether an object is within a detection zone.

According to further aspects of the present invention, multiple obstaclesensors 76 can work together to obtain object sensing. For example, afirst ultrasonic sensor may send out a ping signal. The first ultrasonicsensor and one or more additional ultrasonic sensors may then listen fora response. In this way, the controller may use diversity in identifyingthe existence of an object within one or more of the detection zones.

With reference to FIG. 5, an implementation of multiple speed zonecontrol is illustrated according to yet further aspects of the presentinvention. As illustrated, three detection zones are provided. If anobject such as an obstacle is detected in the first detection zone 78Aand the truck 10 is moving under remote control, then a first action maybe performed, e.g., the truck 10 may be brought to a stop as describedmore fully herein. If an object such as an obstacle is detected in thesecond detection zone 78B and the truck 10 is moving under remotecontrol, then a second action may be performed, e.g., the vehicle speedmay be limited, reduced, etc. Thus, the second detection zone 78B mayfurther designate a first speed zone. For example, the speed of thetruck 10 may be reduced and/or limited to a first relatively slow speed,e.g., approximately 1.5 mph (2.4 Km/h).

If an object such as an obstacle is detected in the third detection zone78C and the truck 10 is moving under remote control, then a third actionmay be performed, e.g., the truck 10 may be reduced in speed orotherwise limited to a second speed, e.g., approximately 2.5 mph (4Km/h). Thus, the third detection zone may further designate a secondspeed zone. If no obstacles are detected in the first, second and thirddetection zones 78A, 78B, 78C, then the vehicle may be remotelycontrolled to travel, e.g., in response to a remote travel request, at arate that is greater than the rate of speed when an obstacle is in thethird detection zone, e.g., a speed of approximately 4 mph (6.2 Km/h).

As FIG. 5 further illustrates, the detection zones may be defined bydifferent patterns relative to the truck 10. Also, in FIG. 5, a seventhobstacle sensor 76 is illustrated for purposes of illustration. By wayof illustration, the seventh obstacle sensor 76 may be approximatelycentered, such as on the bumper or other suitable location on the truck10. On an exemplary truck 10, the third zone 78C may extendapproximately 6.5 feet (2 meters) forward of the power unit 14 of thetruck 10.

According to various aspects of the present invention, any number ofdetection zones of any shape may be implemented. For example, dependingupon desired truck performance, many small zones may be defined atvarious coordinates relative to the truck 10. Similarly, a few largedetection zones may be defined base upon desired truck performance. Asan illustrative example, a database, equation, function or other meansof data comparison, such as a look-up table may be set up in the memoryof the controller. If travel speed while operating under remote travelcontrol is an operational parameter of interest, then the table mayassociate travel speed with the detection zones defined by distance,range, position coordinates or some other measure. If the truck 10 istraveling under remote control and an obstacle sensor detects an object,then the distance to that detected object may be used as a “key” to lookup a corresponding travel speed in the table. The travel speed retrievedfrom the table can be utilized by the controller 103 to adjust the truck10, e.g., to slow it down, etc.

Depending upon factors such as the desired speed of the truck whenoperating under remote control and the required stopping distance, theanticipated load to be transported by the truck 10, whether a certainamount of coast is required for load stability, vehicle reaction time,etc., the areas of each detection zone may be chosen. Moreover, factorssuch as the range of each desired detection zone etc. may be consideredto determine the number of obstacle sensors 76 required. In this regard,such information may be static, or dynamic, e.g., based upon operatorexperience, vehicle load, nature of the load, environmental conditions,etc.

It is also contemplated that the controller 103 may generate a warningsignal or alarm if an object or a person is detected in a detectionzone.

As an illustrative example, in a configuration with multiple detectionzones, e.g., three detection zones, as many as seven or more objectdetectors, e.g., ultrasonic sensors and/or laser sensors may be requiredto provide a range of coverage desired by a corresponding application.In this regard, the detector(s) may be able to look ahead of thedirection of travel of the vehicle by a sufficient distance to allow theappropriate response, e.g., to slow down. In this regard, at least onesensor may be capable of looking several meters forward in the directionof travel of the truck 10.

According to various aspects of the present invention, the multipledetection speed zones allows a relatively greater maximum forward travelspeed while operating under remote control that prevents unnecessarilyearly vehicle stops by providing one or more intermediate zones wherethe vehicle slows down before deciding to come to a complete stop.

According to further aspects of the present invention, the utilizationof multiple detection zones allows a system that rewards thecorresponding operator for better alignment of the truck 10 during pickoperations. For example, an operator may position the truck 10 so as tonot be aligned with a warehouse aisle. As such, as the vehicle is joggedforward, the second detection zone 78B may initially detect an obstaclesuch as a pick bin or warehouse rack. In response to detecting the rack,the vehicle will slow down. If the rack is sensed in the first detectionzone 78A, then the vehicle will come to rest, even if the truck 10 hasnot jogged its entire programmed jog distance. Similar un-necessary slowdowns or stops may also occur in congested and/or messy aisles.

According to various aspects of the present invention, the truck 10 mayshape speed and braking operation parameters based upon the informationobtained from the obstacle sensors 76. Moreover, the logic implementedby the truck 10 in response to the detection zones may be changed orvaried depending upon a desired application. As a few illustrativeexamples, the boundaries of each zone in a multiple zone configurationmay be programably (and/or reprogramably) entered in the controller,e.g., flash programmed. In view of the defined zones, one or moreoperational parameters may be associated with each zone. The establishedoperational parameters may define a condition, e.g., maximum allowabletravel speed, an action, e.g., brake, coast or otherwise come to acontrolled stop, etc. The action may also be an avoidance action. Forexample, an action may comprise adjusting a steer angle or heading ofthe truck 10.

In accordance with a further embodiment of the present invention, one ormore obstacle sensors, such as the obstacle sensors 76A, 76B shown inFIGS. 6 and 8, may be employed to sense or detect objects within first,second and third detection zones in front of the materials handlingvehicle 10 when the vehicle 10 is traveling under remote control inresponse to a travel request command or signal and generate anobject-detected and distance signal to the controller 103 in response tosensing/detecting an object in front of the vehicle 10. A further input104 into the controller 103 may be a weight signal generated by a loadsensor LS, see FIG. 8, which senses the combined weight of the forks 16and any load on the forks 16. The load sensor LS is shown schematicallyin FIGS. 7 and 8 near the forks 16, but may be incorporated into ahydraulic system for effecting lift of the forks 16. By subtracting theweight of the forks 16 (a known constant value) from the combined weightdefined by the weight signal, the controller 103 determines the weightof the load on the forks. Using sensed load weight and whether an objecthas been detected in one of the first, second and third detection zonesas inputs into a lookup table or appropriate equations, the controller103 generates an appropriate vehicle stop or maximum allowable speedsignal.

Values defining the vehicle stop and maximum allowable speed signals maybe experimentally determined and stored in a look-up table, such as theone illustrated in FIG. 11. In the illustrated embodiment, thecontroller 103 determines the weight of a load on the forks 16 andwhether an obstacle has been detected in one of the first, second andthird detection zones and, using the lookup table in FIG. 11, effects astop command or defines a maximum allowable speed for the vehicle 10 andgenerates a corresponding maximum allowable speed signal for the vehicle10.

With reference to the example lookup table in FIG. 11, if no load is onthe forks 16 and no object is being detected by the obstacle sensors76A, 76B in any one of the first, second and third detection zones, thecontroller 103 allows the vehicle to be operated at any speed up to andincluding a maximum speed of 4.5 MPH. As is apparent from FIG. 11, if noobject is being detected in any one of the first, second and thirddetection zones, the maximum permitted speed decreases as the load onthe vehicle increases. For example, for a load weight of 8000 pounds,the maximum allowable speed of the vehicle is 2.5 MPH. It is noted that,in some locations the maximum allowable speed of the vehicle 10, ifunoccupied by a rider, may be set at a predetermined upper limit, e.g.,3.5 MPH. Hence, the maximum speed of the vehicle, if unoccupied by arider, may be set, e.g., by the controller 103, at this maximumallowable speed.

For any load weight on the forks 16, if an object is detected in thefirst detection zone, the controller 103 generates a “stop signal,”designating that the vehicle 10 brake. For any given load weight, themaximum allowable speed of the vehicle is less if an object is detectedin the second or the third detection zone as compared to a state whereno object is being detected. Also for any given load weight, the maximumallowable speed of the vehicle is less if an object is detected in thesecond detection zone as compared to when an object is detected in thethird detection zone. The maximum allowable vehicle speeds for thesecond and third detection zones are defined for each load weight sothat the vehicle's speed can be reduced in a controlled manner as thevehicle continues to move towards the object so that the vehicle caneventually be safely brought to a stop prior to the truck reaching thepoint where the object is located. These speeds are experimentallydetermined and can vary based on vehicle type, size and its brakingcapabilities.

For example, if the load weight on the vehicle equals 1500 pounds, andan object is sensed in the first detection zone, which first zone isnearest to the vehicle power unit 14, then a stop signal is generated bythe controller 103 to effect stopping of the vehicle 10, see FIG. 11. Ifthe load weight on the vehicle remains equal to 1500 pounds, and if asensed object is located at a distance from the vehicle 10 within thesecond detection zone, spaced further away from the power unit 14 thanthe first detection zone, then the maximum allowable vehicle speed isequal to 2.0 MPH, see FIG. 11. Hence, if the vehicle 10 traveling at aspeed greater than 2.0 MPH when the object is detected, the controller103 effects a speed reduction so that the vehicle speed is reduced to2.0 MPH. If the load weight on the vehicle remains equal to 1500 pounds,and if a sensed object is located at a distance within the thirddetection zone, spaced further away from the power unit 14 than thefirst and second detection zones, then the maximum allowable vehiclespeed is equal to 3.0 MPH. Hence, if the vehicle 10 traveling at a speedgreater than 3.0 MPH when the object is detected, the controller 103effects a speed reduction so that the vehicle speed is reduced to 3.0MPH.

The obstacle sensors may comprise ultrasonic transducers. Ultrasonictransducers are known to experience a phenomena known as transducer“ring down.” Essentially “ring down” is the tendency of a transducer tocontinue to vibrate and transmit ultrasonic signals after the controlsignal that is used for initiating a transmitted signal has ceased. This“ring down” signal decreases in magnitude rather rapidly, but during thetime that it is decreasing to a level below a threshold detection level,detection structure forming part of each obstacle sensor will respond tosuch “ring down” signals if the signals are above a reference level andthus can indicate that a “ring down” signal is a reflected or returnsignal when in fact it is not. A common technique to avoid this problemis to blank out all return signals generated by the obstacle sensors fora preselected period of time after initiation of a transmission. Thepreselected time is determined based on various factors including thetype of transducer that is used, but during this preselected time novalid returns can be sensed. If the obstacle sensors are positioned neara front 10A of the vehicle 10, see obstacle sensors 76A in FIG. 7, andif the blanking technique is used, this results in a “dead” or“non-detect” zone DZ existing immediately in front of the vehicle 10.Hence, if an object O is very near the front of the vehicle, e.g., 10 mmor less, and the obstacle sensors 76A are positioned at the front of thevehicle, see FIG. 7, then the object O may not be detected.

In the embodiment illustrated in FIGS. 6 and 8, first and secondobstacle sensors 76A and 76B, respectively, are spaced apart from oneanother along a longitudinal axis L_(A) of the vehicle 10, see FIG. 8.The first obstacle sensors 76A are positioned at the front 10A of thevehicle 10 and are capable of sensing objects in the second and thirddetection zones as well as a first portion of the first detection zone,which first detection zone first portion is a predefined distance aheadof the front 10A of the vehicle 10, e.g., a distance 10 mm or greater infront of the vehicle front 10A. So as to ensure that objects O locatedin the non-detect zone DZ, i.e., an area not sensed by the firstobstacle sensors 76A, the second obstacle sensors 76B are positioned onthe vehicle 10 a spaced distance behind the first sensors 76A, i.e., ina direction away from the vehicle front 10A, see FIG. 8. Hence, thesecond sensors 76B function to sense objects in a first detection zoneremaining second portion Z_(II) just in front of the vehicle front 10Aand corresponding to the dead zone DZ in FIG. 7.

Algorithm

According to various aspects of the present invention, a steercorrection algorithm is implemented, e.g., by the controller 103.Referring to FIG. 12, a steer correction algorithm comprises determiningwhether a steer bumper zone warning is detected at 152. A steer bumpersignal warning at 152 may comprise, for example, detecting the presenceof an object within first and/or second steer bumper zones 132A, 132Bwith a laser sensor 2000, such as a model number LMS 100 or LMS 111laser sensor manufactured by Sick AG located in Waldkirch, Germany. Thelaser sensor 2000 may be mounted to the power unit 14, see FIG. 13. Thefirst steer bumper zone 132A may also be designated as a left steerbumper zone and the second steer bumper zone 132B may also be designatedas a right steer bumper zone, see FIG. 13. If a steer bumper zonewarning is received, a determination is made at 154 whether the steerbumper zone warning indicates that an object is detected to the left orto the right of the truck 10, e.g., whether the detected object is inthe first steer bumper zone 132A or the second steer bumper zone 132B.For example, the laser sensor 2000 may generate two outputs, a firstoutput signal designating whether an object is detected in the first(left) steer bumper zone 132A, and a second signal designating whetheran object is detected in the second (right) steer bumper zone 132B.Alternatively, the controller 103 may receive raw laser sensor data andprocess/distinguish the first and second steer bumper zones 132A, 132Busing a predetermined mapping.

For example, referring additionally to FIG. 13, the laser sensor 2000may sweep a laser beam in an area in front of truck 10. In this regard,multiple laser sensors may be utilized, or one or more laser beams maybe swept, e.g., to raster scan one or more areas forward of the truck10. If an object is present in an area where the laser beams are swept,the object reflects the beam back to the laser sensor 2000, which iscapable of generating object location data from which the location ofthe sensed object can be determined either by the sensor 2000 or thecontroller 103, as is known in the laser sensor art. In this regard, thelaser sensor 2000 may independently define and scan the left and rightsteer bumper zones, or the controller 103 may derive the left and/orright steer bumper zones based upon the raster scan of the laser(s).Still further, alternate scanning patterns may be utilized, so long asthe controller 103 can determine whether a detected obstacle is to theleft or to the right of the truck 10.

As a few additional examples, although a laser sensor 2000 isillustrated for purposes of discussion herein, other sensingtechnologies may be utilized, examples of which may include ultrasonicsensors, infrared sensors, etc. For example, ultrasonic sensors, e.g.,located to the sides of the truck 10, may define the left and rightsteer bumper zones 132A, 132B. Selection of the type(s) of sensors usedon the truck 10 may depend upon the particular operating conditions ofthe truck 10.

Additionally, the laser sensor 2000 or one or more additional sensorsmay be used to define other detection zones, e.g., for stopping, speedlimiting, etc. The laser sensor 2000 (or one or more additional sensors)may define a “stop zone”, and/or a “slow down zone” as described indetail herein. For example, if a single stop zone is defined and anobject is detected in the stop zone, which may extend, for example,about 1.2 meters in front of a forward traveling direction of the truck10, the controller 103 may cause the truck 10 to stop, as set out indetail herein. Additionally or alternatively, if an object is detectedin a slow down zone, the controller 103 may cause the truck 10 to slowdown. It is noted that, according to this embodiment, it may bepreferable to define a stop zone while not defining a slow down zone.

Further, the truck 10 may comprise one or more load presence sensors 53,see FIG. 13. The load presence sensor(s) 53 may comprise proximity orcontact technology, e.g., a contact switch, a pressure sensor, anultrasonic sensor, optical recognition device, infrared sensor or othersuitable technology that detects the presence of a suitable loadcarrying structure 55, e.g., a pallet or other platform, collectioncage, etc. The controller 103 may refuse to implement a travel commandif one or more of the load presence sensors 53 indicate that the loadplatform 55 is not in a valid designated position. Still further, thecontroller 103 may communicate with the brake controller 108 to stop thetruck 10 if the load presence sensors 53 detect a change of the loadplatform 55 from a valid designated position.

It should be understood that any number of detection zones may beimplemented, and the implemented detection zones may overlap or definediscrete, mutually exclusive zones. Depending upon the sensor and sensorprocessing technologies utilized, the input(s) to the controller 103designating an object in the steer bumper zones 132A, 132B may be inother formats. As yet a further illustration, the first and second lasersteer bumper zones 132A, 132B may be defined by both ultrasonic sensorsand one or more laser sensors. For example, the laser sensor 2000 may beutilized as a redundant check to verify that the ultrasonic sensorsproperly detect an object in either the left or right steer bumper zones132A, 132B, or vice versa. As yet a further example, ultrasonic sensorsmay be utilized to detect an object in the left or right steer bumperzones 132A, 132B and the laser sensor 2000 may be utilized todistinguish or otherwise locate the object to determine whether theobject was detected in the left steer bumper zone 132A or the rightsteer bumper zone 132B. Other arrangements and configurations mayalternatively be implemented.

If a steer bumper zone warning designates that an object is detected inthe left steer bumper zone 132A, then a steer correction routine isimplemented at 156 that includes computing a steer angle correction tosteer the truck 10 to the right according to a first set of parameters.By way of illustration and not by way of limitation, a steer rightcorrection implemented at 156 may include steering the truck 10 to theright at a right direction steer angle. In this regard, the rightdirection steer angle may be fixed or variable. For example, thecontroller 103 may command the steer controller 112 to ramp up to somedesired steer angle, e.g., 8-10 degrees to the right. By ramping up to afixed steer angle, sudden changes in the angle of the steer wheel(s)will not occur, resulting in a smoother performance. The algorithmaccumulates the distance traveled at the steer correction angle, whichmay be a function of how long the appropriate steer bumper input isengaged.

According to various aspects of the present invention, the steered wheelangular change may be controlled to achieve, for example, asubstantially fixed truck angle correction as a function of accumulatedtravel distance. The travel distance accumulated while performing asteer correction maneuver may be determined based upon any number ofparameters. For example, the distance traveled during the steercorrection may comprise the distance traveled by the truck 10 until thedetected object is no longer within the associated left bumper detectionzone 132A. The accumulated travel distance may also/alternativelycomprise, for example, traveling until a time out is encountered,another object is detected in any one of the bumper or detection zones,and/or predetermined maximum steer angle is exceeded, etc.

Upon exiting a right steer correction at 156, e.g., by maneuvering thetruck 10 so that no object is detected within the left steer bumperdetection zone 132A, a left steer compensation maneuver is implementedat 158. The left steer compensation maneuver at 158 may comprise, forexample, implementing a counter steer to adjust the travel direction ofthe truck 10 to an appropriate heading. For example, the left steercompensation maneuver may comprise steering the truck 10 at a selectedor otherwise determined angle for a distance that is a percentage of thepreviously accumulated travel distance. The left steer angle utilizedfor the left steer compensation maneuver may be fixed or variable, andmay be the same as, or different from the steer angle utilized toimplement the right steer correction at 156.

By way of illustration and not by way of limitation, the distanceutilized for the left steer compensation maneuver at 158 may beapproximately one quarter to one half of the accumulated travel distancewhile implementing the right steer correction at 156. Similarly, theleft steer angle to implement the left steer compensation maneuver maybe approximately one half of the angle utilized to implement the rightsteer correction at 156. Thus, assume that the right steer angle is 8degrees and the accumulated steer correction travel distance is 1 meter.In this example, the left steer compensation may be approximately onehalf of right steer correction, or −4 degrees, and the left steercompensation will occur for a travel distance of approximately ¼ metersto ½ meters.

The particular distance and/or angle associated with the left steercompensation maneuver at 158 may be selected, for example, so as todampen the “bounce” of the truck 10 as the truck 10 moves along itscourse to steer correct away from detected obstacles. As anillustration, if the truck 10 steer corrects at a fixed degrees perdistance traveled, the controller 103 may be able to determine how muchthe corresponding truck angle has changed, and therefore, adjust theleft steer compensation maneuver at 158 to correct back towards theoriginal or other suitable heading. Thus, the truck 10 will avoid “pingponging” down an aisle and instead, converge to a substantially straightheading down the center of the aisle without tedious manualrepositioning required by the truck operator. Moreover, the left steercompensation maneuver at 158 may vary depending upon the particularparameters utilized to implement the right steer correction at 156.

Correspondingly, if a steer bumper zone warning designates that anobject is detected in the right steer bumper zone 132B, then a steercorrection routine is implemented at 160 that includes computing a steerangle correction to steer the truck 10 to the left according to a secondset of parameters. By way of illustration and not by way of limitation,a steer left correction implemented at 160 may include steering thetruck 10 to the left at a left steer angle. In this regard, the leftsteer correction maneuver at 160 may be implemented in a manneranalogous to that described above at 156, except that the correction isto the right at 156 and to the left at 160.

Similarly, upon exiting a left steer correction at 160, e.g., bymaneuvering the truck 10 so that no object is detected within the rightbumper detection zone 132B, a right steer compensation maneuver isimplemented at 162. The right steer compensation maneuver at 162 maycomprise, for example, implementing a counter steer to adjust the traveldirection of the truck 10 to an appropriate heading in a manneranalogous to that described at 158, except that the steer compensationmaneuver at 158 is to the left and the steer compensation maneuver at162 is to the right.

After implementing the steer compensation maneuver at 158 or 162, thetruck may return to a substantially straight heading, e.g., 0 degrees at164 and the process loops back to the beginning to wait for thedetection of another object in either of the steer bumper zones 132A,132B.

The algorithm can further be modified to follow various control logicimplementations and/or state machines to facilitate various anticipatedcircumstances. For example, it is possible that a second object willmove into either steer bumper zone 132A or 132B while in the process ofimplementing a steer compensation maneuver. In this regard, the truck 10may iteratively attempt to steer correct around the second object. Asanother illustrative example, if object(s) are simultaneously detectedin both the left and right steer bumper zones 132A, 132B, the controller103 may be programmed to maintain the truck 10 at its current heading(e.g., zero degree steer angle), until either one or more steer bumperzones 132A, 132B are cleared or the associated detection zones cause thetruck 10 to come to a stop.

According to further aspects of the present invention, a user and/orservice representative may be able to customize the response of thesteer angle correction algorithm parameters. For example, a servicerepresentative may have access to programming tools to load customizedvariables, e.g., in the controller 103, for implementing steercorrection. As an alternative, a truck operator may have controls thatallow the operator to input customized parameters into the controller,e.g., via potentiometers, encoders, a software user interface, etc.

The output of the algorithm illustrated in FIG. 12 may comprise, forexample, an output that defines a steer correction value that may becoupled from the controller 103 to an appropriate control mechanism ofthe truck 10. For example, the steer correction value may comprise a +/−steer correction value, e.g., corresponding to steer left or steerright, that is coupled to a vehicle control module, steer controller112, e.g., as illustrated in FIG. 2, or other suitable controller. Stillfurther, additional parameters that may be editable, e.g., to adjustoperational feel may comprise the steer correction angle, a steercorrection angle ramp rate, a bumper detection zone size/range for eachsteer bumper zone, truck speed while steer correcting, etc.

Referring to FIG. 13, assume in the illustrative example, that the truck10 is traveling in response to receiving a remote wireless travelrequest and that before the truck 10 can travel a predetermined jogdistance, the truck 10 travels into a position where a rack leg 1720 anda corresponding pallet 1740 are in the path of the left steer bumperzone 132A. Keeping with the exemplary algorithm of FIG. 12, the truck10, e.g., via the controller 103, may implement an obstacle avoidancemaneuver by entering a steer correction algorithm, to steer the truck tothe right. For example, the controller 103 may compute or otherwiselookup or retrieve a steer correction angle that is communicated to asteer controller 112 to turn the drive wheel(s) of the truck 10.

The truck 10 maintains steer correction until an event occurs, such asthe disengagement of the object, e.g., when the scanning laser or otherimplemented sensor technology no longer detects an object in the leftsteer bumper zone 132. Assume that the truck 10 accumulated a traveldistance of one half of a meter during the steer correction maneuver,which was fixed at 8 degrees. Upon detecting that the left steer bumperzone signal has disengaged, a counter steer compensation is implementedto compensate for the change in heading caused by the steer correction.By way of example the steer compensation may steer the truck 10 to theleft for approximately one quarter meter accumulated travel distance, at4 degrees. For very narrow aisles, the Left/Right steer bumper zonesensors may provide very frequent inputs /little time between sensescompared to relatively wider aisles.

The various steer angle corrections and corresponding counter steercompensations may be determined empirically, or the angles, ramp rates,accumulated distances, etc., may be computed, modeled or otherwisederived.

In the illustrative arrangement, the system will try to maintain thetruck 10 centered in the aisle as the truck 10 advances in response toreceiving a corresponding wirelessly transmitted travel request by thetransmitter 70. Moreover, bounce, e.g., as measured by the distance fromthe centerline of a warehouse aisle, is damped. Still further, there maybe certain conditions where the truck 10 may still require some operatorintervention in order to maneuver around certain objects in the line oftravel.

The description of the present invention has been presented for purposesof illustration and description, but is not intended to be exhaustive orlimited to the invention in the form disclosed. Many modifications andvariations will be apparent to those of ordinary skill in the artwithout departing from the scope and spirit of the invention.

Having thus described the invention of the present application in detailand by reference to embodiments thereof, it will be apparent thatmodifications and variations are possible without departing from thescope of the invention defined in the appended claims.

1. A finger-mounted remote control device capable of wirelesslytransmitting a travel request signal to a materials handling vehiclecomprising: a rigid mounting structure adapted to be mounted over atleast one finger of an operator's hand; a mounting strap coupled to saidrigid mounting structure for securing said rigid mounting structure tothe at least one finger; a wireless transmitter/power pack unit coupledto said rigid mounting structure; and control structure coupled to saidmounting structure and comprising a switch adapted to be actuated by anoperator's thumb so as to cause said wireless transmitter/power packunit to generate a travel request signal to the materials handlingvehicle.
 2. The control device of claim 1, wherein said mounting strapcontacts the at least one finger of the operator's hand.
 3. The controldevice of claim 1, wherein said rigid mounting structure is formed froma rigid polymeric material.
 4. The control device of claim 1, whereinsubstantially the entirety of said control device is mounted andpositioned directly over the at least one finger of the operator's hand.5. The control device of claim 4, wherein approximately 60% or more ofsaid wireless transmitter/power pack unit is positioned directly overthe at least one finger of the operator's hand.
 6. A finger-mountedremote control device capable of wirelessly transmitting a travelrequest signal to a materials handling vehicle comprising: a mountingstructure adapted to be mounted over at least one finger of anoperator's hand; a mounting strap coupled to said mounting structure forsecuring the mounting structure to the at least one finger; a wirelesstransmitter/power pack unit coupled to said mounting structure; andcontrol structure coupled to said mounting structure and comprising aswitch adapted to be actuated by an operator's thumb so as to cause saidwireless transmitter/power pack unit to generate a travel request signalto the materials handling vehicle; wherein substantially the entirety ofsaid control device is mounted and positioned directly over the at leastone finger of the operator's hand.
 7. The control device of claim 6,wherein approximately 60% or more of said wireless transmitter/powerpack unit is positioned directly over the at least one finger of theoperator's hand.
 8. A materials handling vehicle comprising: a powerunit; a load handling assembly coupled to said power unit; at least oneobstacle detector mounted to said power unit to detect an object locatedalong a path of travel of said power unit, said detector generating adistance signal upon detecting an object corresponding to a distancebetween the detected object and said power unit; and a controllerreceiving said distance signal and generating a corresponding vehiclestop or maximum allowable speed signal based on said distance signal. 9.The materials handling vehicle as set out in claim 8, further comprisinga load sensor to generate a weight signal indicative of a weight of aload on said load handling assembly.
 10. The materials handling vehicleas set out in claim 9, wherein said controller receives said distancesignal and said weight signal and generates a corresponding vehicle stopor maximum allowable speed signal based on said distance and weightsignals.
 11. The materials handling vehicle as set out in claim 10,wherein for a given first load weight, if a sensed object is located ata distance within a first detection zone, a stop signal is generated bysaid controller to effect stopping of said vehicle.
 12. The materialshandling vehicle as set out in claim 11, wherein for said given firstload weight, if a sensed object is located at a distance within a seconddetection zone spaced further away from said power unit than said firstdetection zone, then a first maximum allowable vehicle speed is definedcorresponding to said first load weight and an object being detected insaid second detection zone.
 13. The materials handling vehicle as setout in claim 12, wherein for said given first load weight, if a sensedobject is located at a distance within a third detection zone spacedfurther away from said power unit than said first and second detectionzones, then a second maximum allowable vehicle speed greater than saidfirst maximum is defined corresponding to said first load weight and anobject being detected in said third detection zone.
 14. A materialshandling vehicle comprising: a power unit; a load handling assemblycoupled to said power unit; at least one obstacle detector mounted tosaid power unit to detect an object located along a path of travel ofsaid power unit, said detector generating a distance signal upondetecting an object corresponding to a distance between the detectedobject and said power unit; a load sensor to generate a weight signalindicative of a weight of a load on said load handling assembly; and acontroller receiving said distance signal and said weight signal andgenerating a corresponding vehicle stop or maximum allowable speedsignal based on said distance and weight signals.
 15. The materialshandling vehicle as set out in claim 14, wherein for a given first loadweight, if a sensed object is located at a distance within a firstdetection zone, a stop signal is generated by said controller to effectstopping of said vehicle.
 16. The materials handling vehicle as set outin claim 15, wherein for said given first load weight, if a sensedobject is located at a distance within a second detection zone spacedfurther away from said power unit than said first detection zone, then afirst maximum allowable vehicle speed is defined corresponding to saidfirst load weight and an object being detected in said second detectionzone.
 17. The materials handling vehicle as set out in claim 16, whereinfor said given first load weight, if a sensed object is located at adistance within a third detection zone spaced further away from saidpower unit than said first and second detection zones, then a secondmaximum allowable vehicle speed greater than said first maximum isdefined corresponding to said first load weight and an object beingdetected in said third detection zone.
 18. A materials handling vehiclecomprising: a power unit; a load handling assembly coupled to said powerunit; at least one first obstacle detector mounted at a first locationon said power unit to detect an object located along a path of travel ofsaid power unit beyond a dead zone of said first detector; and at leastone second obstacle detector mounted at a second location on said powerunit, spaced from said power unit first location, and capable ofdetecting an object in said dead zone of said first obstacle detector.19. The materials handling vehicle as set out in claim 18, wherein saidfirst obstacle detector is located at a front portion of said powerunit.
 20. The materials handling vehicle as set out in claim 19, whereinsaid second obstacle detector is spaced away from said first obstacledetector in a direction towards said load handling assembly.